# 函数的某些参数强制使用关键字参数传递
# 将强制关键字参数放到某个* 参数或者当个* 后面就能达到这种效果

def recv(maxsize, *, block):
    'Receive a message'
    pass
recv(1024, True) # TypeError
recv(1024, block = True) # OK
